Traditionally, engines in aircraft, including airplanes and helicopters, as well as land vehicles, require an uninterrupted flow of clean fuel from fuel structures, such as fuel tanks, fuel cells, fuel bladders, and the like, to the engines for proper operation. These systems commonly include fuel systems that are designed to prevent water or other contaminants from entering the engine during operation. For example, many of these systems rely on the fact that most fuels, such as jet fuel, gasoline, diesel, ethanol, and other similar fuels, are less dense than water and other contaminants. Thus, the water or other contaminant will separate from the fuel and settle to the bottom of the fuel container.
In many cases, a sump is added to the bottom of the fuel container as a location to collect the water or other contaminant. The sump includes a sump cavity that typically forms the lowest point in a lower surface of the fuel container. A drain valve or bleed valve may be included in a lower surface of the sump cavity as a mechanism to remove the water or other contaminants that may have settled into the sump cavity.
The sumps are traditionally formed of metallic or other rigid materials, which are chosen to provide structural integrity and rigidity to the sump to withstand the force of an impact. Because the sump forms the lowest surface in the fuel tank, the sump is positioned in a location that may protrude from a lower surface of the aircraft or land vehicle. This position often subjects the sump to damage when the aircraft or vehicle suffers a crash impact. In many cases, the sump is not strong enough to withstand the force of impact, which may result in undesirable fuel leaks during impact caused by cracks or other structural failures. Accordingly, it may be desirable to develop a flexible sump design that may accept high deformation without risks of leaks to maintain the integrity of the fuel tank in the event of a crash impact.